Speed varying transmission



w. A. DUFFIELD 2,498,797

SPEED VARYING TRANSMISSION 2 Sheets-Sheet 1 Feb. 28, 1950 Filed July 12,1944 NAN Feb. 28,' 1950 w. A. DUFFIELD 2,498,797

SPEED VARYING TRANSMISSION Filed July 12, 1944 2 Sheets-Shea*l 2 a i:.f6 57 if v rime/VE ys.

Patented Feb. 28, 1950 UNITED' sTAr wiiuam A. namen, winger, ontario,canada; f assignor, by mesneassignm'entatowindelds u .1946 Limited,Montreal',v guebect Canada/,a cor.

poration of ,Canada Applicatie; 12,-v mug-serial ,North-,suoi y 1 Theobject of my invention is to provide an automatic speed-varyingtransmission unit havv ing a normal at rest high-speed coordination andautomatically responsive to a predetermined differential between inputtorque and output torque to determine the gear ratio at which the unitwill function.

The accompanying drawings illustrate my invention.

Fig. 1 is an axial section of an embodiment of my invention;

Fig. 2 is an axial section of reversing and idling means supplementingmy invention;

Fig. 3 is a section on line 3 3 of Fig. l;

Fig. 4 is a section on line 4-4 of Fig. 1; and

Fig. 5 is a fragmentary section through one of the clutch-controllingtoggles.

My transmission unit in its preferred form comprises, fundamentally, twoinput sun gears, an output sun gear, a planet gear unit meshingsimultaneously with said sun gears, a carrier for said planet gear unit,an output shaft, a clutch normally connecting said carrier and outputshaft for unitary rotation, and a connection between the output sun gearand said clutch responsive to a predetermined differential between inputtorque and load torque applied to the output shaft to disconnect thenormal clutch connection between the planet carrier and the outputshaft.

Referring to the drawings, I0 indicates an input shaft provided with theinput sun gear il. Sleeved upon shaft I0 is a sleeve shaft I2 providedwith the input sun gear I3. Sleeved upon shaft I0 is output shaft I4,upon the inner end of which is sleeved the output sun gear I5, having ahub I5 connected to the hub I6' of a spider I6 sleeved on output shaftI4 and connected to hub I5 by a jaw clutch I5".

Journalled on shaft I2 and hubs I5', I6 is a planet carrier I1 carryinga plurality of circumferentially spaced planet shafts I8 upon each ofwhich is journalled a planet gear unit P com prising three gears I9, 20and 2I meshing, respectively, with sun gears II, I3 and I5. Coaxial withcarrier I1 is a brake drum |10 between which and carrier I1 isinterposed a one-way clutch I1I which will prevent reverse rotation ofcarrier I1 whenever drum |10 is held against rotation by a manuallycontrollable brake band I 12.

Output shaft I4 is provided with a circumferential flange 22 providedwith a plurality of circumferentially spaced pins 22' to which issecured the clutch shell 30 having circumferen- "ualiy 'spacdfpms 2s,

upon each of which is pivoted avbell-crank lever 24 one arm of eachbeing projected radially inwardly and provided with a pocket 24 in whichis journalled a pin 24 having a diametrical slot 25 into which is'projected a radial finger I6 of spider I6. The

other arm of each lever 24 is projected tangen- -tially relative toflange 22 and is provided with a pocket 24" in which is nested toggle Tcomprising two lever arms 26, 26 pivoted together at 21. The oppositeprojecting free ends of arms 26, 26 are nested, respectively, in blocks28" and 30".

' Blocks 30 are rotatively supported in pockets formed in the clutchshell 30 which is coaxial with carrier I1, and blocks 28" are mounted inthe fulcrum ring 38. Shell 30 is provided with an abutment ring 32 and apressure ring 33 between which are interdigitated friction rings 34, ofwell known form, splined alternately to shell 30 and carrier I1. Ring 33is urged to clamping position by circumferentially spaced springs 35carried by shell 30 and is provided with a plurality ofcircumferentially spaced pull rods 36 to the outer end of each of whichis connected a lever 31 the inner end of which is projected radiallytoward the axis of shaft I0. Ring 38 floats on the left-hand (Fig. 1)ends of toggles T, being urged thereon by springs 35, pins 36 and levers31.

The levers 31 overlie the fulcrum ring 38 and their inner ends areengaged by a shift-collar 39 on output shaft I4 the arrangement beingsuch that when collar 39 is shifted to the right (Fig. 1) pressure ring33 is withdrawn from the clutch rings 34 and the normal connectionbetween carrier I1 and output shaft I4 is rendered ineffective. When thevtoggle carrying arms of levers 24 are moved inwardly, the toggles T,acting on fulcrum ring 38, also serve to withdraw pressure ring 33 fromclutch rings 34 to render ineffective the clutch connection betweencarrier I1 and output shaft I4.

In order to provide input torque to the two input sun gears, I preferthe following mechanism:

The power source shaft 40 carries the impeller 4I of a uid couplingwhich also comprises a first runner 42 and a second runner 43, saidimpeller and runners having axially vaned passages 4I, 42 and 43' soarranged that the torroidal flow of the coupling uid will be fromimpeller 4 I through runner 43, and thence through runner 42 back to theimpeller, so that the drive exerted by impeller 4I will be primarilyupon runner 42 and secondarily upon runner 43.

Runner 42 is connected to input shaft I0 through the medium of a.one-way clutch 44 which will permit shaft I to run forwardly at a speedexceeding that of runner 42. Runner 43 is splined upon the input shaftI2.

Operation is as follows:

Rotation of impeller 4I exerts a fluid drive on runner 42 and,.throughrunner 42, upon runner 43.

Initial torque ilow will be 4I, 42, I0, II, I9, 2|, I5, I6, I6, 24, 23,30, 22, I4. It will be noticed that the force applied to 24 from I6'tends to swing the toggle arms of 24 inwardly and that if such movementoccurs the clutch connection between I1 and I4 will be disrupted. If thedifferential between input torque and load torque is not too great,however, the clutch connection between I1 and I4 will persist and theload will be picked up by the transmission acting as a unit in 1 to 1ratio, except for the uid slip between 4| and 52.

If the operator depresses his accelerator lever enough to produce atorque differential as much as the force required to break the clutchconnection between I1 and I4 the torque flow will be either 4I, 42. I0,II, I9, 2l, I5, I6, etc., or 4I, 42, 43, I2, I3, 20, 2l, I5, I6, etc.,or both, depending upon the amount of that differential and the speedsof the first and second runners relative to each other and to theimpeller, so that transmission will be through the unit at less than a 1to 1 ratio.

As the speed of the load picks up, centrifugal forces acting on levers24 to tend to swing the toggle-bearing ends of lever 24 outwardly torestore the clutch connection between -I1 and I4.

It will be apparent, therefore, that there is a constant tendency in theapparatus to assume a I to I driving ratio and that, although, at alltimes, the operator, by proper manipulation of -his accelerator lever,may influence the gear ratio at which the unit will function,nevertheless the unit will automatically adjust itself to the gear ratiowhich is most eicient for the load at the instant torque diierential.

Any desired means may be provided to transmit power from the outputshaft to an ultimate tail shaft selectively for forward or reversedrive. In the drawings I have illustrated a well known form ofsynchronizing selective means which also affords a neutral relation.

Output shaft I4 carries a gear 50 which meshes with a planet gear 5Icarried by a carrier 52 journalled on shaft I4. Gear 5I meshes with aninternal orbit gear 53 carried by tailshaft 54 and provided with afriction drum 55 mated by the synchronizing ring 56. A

Splined on carrier 52 is the clutch collar 51 having peripheral teethcapable of interlocking with the teeth of the orbit gear 53 and alsocapable of penetrating ring 56. A second synchronizing ring 58 mating axed friction drum 59 carried by casing X also coacts with clutch collar51. When these parts are in the positions shown in Fig. 1, carrier 52 isfree to rotate so that planet gear 5I rotates and revolves freely withinthe orbit gear without transmitting substantialy torque to thetailshaft. When clutch collar 51 is shifted to the left, Fig. 2, it isfirst synchronized with, and then enters, gear 53 to clutch the carrier52 and the tailshaft together for forward drive. When collar 51 isshifted to the right,

Fig. l, carrier 52 is tied to casing X and reverse drive is obtainedthrough the gear 5I.

The requisite connection between the output shaft and tailshaft may bewidely varied without departing from my invention, and the mechanismjust described for this purpose forms no part of my present invention.

The clutch connection between the planet carrier I1 and output shaft I4preferably should be disestablished when shifting from neutral toforward or reverse and various arrangements may be provided to this end.

For instance, a manually controllable lever 60 for clutch 51 may engageeither of two lugs 6I' on a lever 6I pivoted at 62 and connected by link63 to one arm of a bell crank lever 64 connected by link 65 to a lever66 acting on collar 39, and serves to momentarily release the clutchmechanism between I1 and I4 as clutch 41 passes from neutral position toeither forward or reverse position.

It should be noted (Fig. 5) that toggles T are placed with the outerends of lever arms 26 directed inwardly toward the axis of shaft I 0 sothat the pivotal junction between lever arms 26 is capable of exertingan outward thrust on the Weighted arm of element 24 serving to swingsaid element 24 about its pivot 23 to its outward limit (Fig. 3), whenfulcrum ring 38 is moved toward shell 30 by springs 35, due to the factthat the force of said springs tends to move the outer ends of leverarms 26 (Fig. 5) toward each other and thus force the pivotal junctionof said lever arms outwardly relative to the axis of shaft I0.

I claim as my invention: l 5;

l. In a variable-speed transmission, two/ibependently actuatable inputgears, an output gear, a planetary gear unit including a unitary toothedelement meshing with said three gears to interlock the same, a rotatablecarrier for said planetary gear, means for locking said carrier againstreverse rotation, a clutch interposed between said carrier and outputgear and normally biased to clutch position, an output shaft, and meansinterposed between said output gear and output shaft for actuating saidclutch in opposition to its bias.

2. Apparatus of the character specified in claim 1, where in theconnection between the output gear and output shaft comprises ayieldable connection between the output gear and the output shaftresponsive to a differential between input torque and load torque andassociated with means for releasing the clutch in response tooverpowering input torque.

3. Apparatus of the character specied in claim 1 and including atailshaft, reversing gearing, means for selectively coupling the outputgear with the tailshaft with or without interposition of the reversinggearing, and means actuated by said selective means for temporarilyreleasing the clutch between the planet carrier and output gear intransition to and from an intermediate position of said selective means.

4. Apparatus of the character specied in claim 1 and including a fluidcoupling comprising an impeller and two runners with one runnerconnected to one input gear through a one-way clutch and the otherconnected to the other input gear, a tailshaft, reversing gearing, meansfor selectively coupling the output gear with or without interpositionof the reversing gearing, and means actuated by said selective means fortemporarily releasing the clutch between the planet carrier and outputgear in transition to and from intermediate position of said selectivemeans.

5. In a variable-speed transmission, two independently actuatable inputsun gears, an output sun gear, a planetary gear unit comprising aunitary toothed element meshing with said three gears, a carrier forsaid planetary gear coaxial with the sun gears, a clutch interposedbetween said carrier and output gear and normally biased to clutchingposition, an output shaft, and means interposed between said output gearand output shaft for actuating said clutch in opposition to its bias.

6. Apparatus of the character specified in claim 5, wherein theconnection between the output gear and output shaft comprises ayieldable connection responsive to a differential between input torqueand load torque and associated with means for releasing the clutch inresponse to overpowering input torque.

'7. Apparatus of the character specified in claim 5, wherein theconnection between the output gear and output shaft comprises ayieldable connection between the output gear and output shaft associatedwith means for releasing the clutch in response to overpowering inputtorque, and including a tail shaft, reversing gearing, means forselectively coupling the output shaft with the tail shaft with orwithout interposition of the reversing gearing, and means actuated bysaid selective means for temporarily releasing the clutch between planetcarrier and output gear in transition to and from an intermediateposition of said selective means.

8. Apparatus of the character specified in claim 5, and including afluid coupling comprising an impeller and two runners with one runnerconnected to one sun gear through a one-way clutch and the other runnerconnected to the other sun gear, a tailshaft, reversing gearing, meansfor selectively coupling the output gears with or without interpositionof the reversing gearing, and means actuated by said selective means fortemporarily releasing the clutch between the planet carrier and outputgear in transition to and from intermediate position of said selectivemeans.

9. A speed-varying transmission comprising two independently actuatableinput gears, an output gear, gears meshing with said three gears andproviding one ratio train between one input gear and the output gear anda second ratio train between the other input gear and the output gear,an output shaft, a clutch normally biased to couple the input gears andoutput gear as a unit to the output shaft, and means interposed betweenthe output gear and output shaft responsive to a predetermineddifferential between input torque and output torque to actuate saidclutch in opposition to its bias, a tailshaft, reversing gearing, meansfor selectively coupling the output shaft with the tailshaft with orwithout interposition of the reversing gearing, and means actuated bysaid selective means for temporarily releasing the clutch in transitionto and from an intermediate position of said selective means.

10. A speed-varying transmission comprising two independently actuatableinput gears, an output gear, gears meshing with said three gears andproviding one ratio train between one input gear and the output gear anda second ratio train between the other input gear and the output gear,an output shaft, a clutch normally biased to couple the input gears andoutput gear as a unit to the output shaft, and means interposed betweenthe output gear and output shaft responsive to a predetermineddifferential between input torque and output torque to actuate said'clutch in opposition to its bias, a fluid coupling comprising animpeller and two runners with one runner connected to one input gearthrough a one-Way clutch and the other runner connected to the otherinput gear. a tailshaft, reversing gearing, means for selectivelycoupling the output shaft with the tailshaft with or withoutinterposition of the reversing gearing, and means actuated by saidselective means for temporarily releasing the biased clutch intransition to and from an intermediate position of said selective means.

11. In a variable-speed transmission, two input members to which powermay be applied, an output member, a speed reduction train between one ofsaid input members and the output member, a speed reduction trainbetween the other of said input members and the output member, a clutchnormally biased to unify the connection between said input members andoutput member, means responsive to a predetermined difference betweeninput torque and load torque to actuate said clutch in opposition to itsbias, a tailshaft, reversing gearing, means for selectively coupling theoutput member with the tailshaft with or without interposition of thereversing gearing, and means actuated by said selective means fortemporarily releasing the biased clutch in transi- 30 tion to and froman intermediate position of said selective means.

12. In a variable-speed transmission, two input members to which powermay be applied, anV

output member, a speed reduction train between one of said input membersand the output member, a speed reduction train between the other of saidinput members and the output member, a clutch normally biased to unifythe connection between said input members and output member, meansresponsive to a predetermined difference between input torque and loadtorque to actuate said clutch in opposition to its bias, a fluidcoupling comprising an impeller and two runners with one runnerconnected to one input member through a one-Way clutch and the otherrunner connected to the other input member, a tailshaft, reversinggearing, means for selectively coupling the output member with thetailshaft with or`without interposition of the reversing gearing, andmeans actuated by said selective means for temporarily releasing thebiased clutch in transition to and from an intermediate position of saidselective means.

13. In a speed change gearing of the type comprising an input sun gear,a coaxial output gear, a planet unit gear meshing with said input andoutput gears, a tail shaft, a carrier for said planet gear coaxial withthe input and output gears, and a clutch between the carrier and tailshaft; 60 means yieldingly biasing said clutch to active position, acentrifugally sensitive weight between said clutch and tail shaft topartake of tail-shaft speed, a toggle carried by said weight and abutingsaid tail shaft and clutch in opposi- 65 tion to the clutch-biasingmeans and so positioned that movement of the toggle toward the axis ofinput and output gears will overcome said biasing means to render theclutch ineffective, and a connection responsive to forward move- 'l0ment of the output gear relative to the tail shaft to shift said toggleto overcome the clutch biasing means.

14. Apparatus of the character specified in claim 13 and includingmeans, independent of Il the centrifugally sensitive weight, to overcomegears, a rotatable carrier for said planetary gear,

means for locking said carrier against reverse rotation, a clutchinterposed between said carrier and output gear, means normally biasingsaid clutch to engaged condition, an output shaft, and means providing adriving connection between said output gear and said output shaft, saidlastnamed means including a first element movable with said output gear,a second element movable with said output shaft and movable relative tosaid output shaft, said elements being drivingly connected, and meansactuated by movement of said second element relative to said outputshaft i under the infiuence of power applied thereto by said firstelement, to disengage said clutch.

16. In a variable-speed transmission, two independently actuable sungears, an output sun gear, a planetary gear unit meshing with said threegears, a carrier for said planetary gear coaxial with the sun gears, aclutch interposed between said carrier and output gear, means normallybiasing said clutch to engaged condition, an output shaft, and meansproviding a driving connection between said output gear and said outputshaft, said last-named means including a ilrst element movable with saidoutput gear, a second element movable with said output shaft and movablerelative to said output shaft, said elements being drivingly connected,and means actuated by movement of said second element relative to saidoutput shaft under the inuence of power applied thereto by said firstelement, to disengage said clutch.

WILLIAM A. DUFFIELD.

REFERENCES CITED The following references'are of record in the ille ofthis patent:

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